The present invention provides known and novel compounds, their use in the inhibition of an enzyme whose preferred mode of action is to catalyse the hydrolysis of an ester functionality (in vivo, as the enzyme naturally occurs), their use in medicine, and particularly in the prevention and/or treatment of obesity or an obesity-related disorder. Also provided are methods for the prevention and/or treatment of obesity or an obesity-related disorder and for promoting/aiding non-medical weight loss and the use of the compounds in the manufacture of a medicament for the aforementioned indications. In respect of novel compounds the invention also provides processes for their manufacture, compositions containing them, and methods for manufacturing such compositions.
In the last 20 years, there has been an increasing trend in obesity in the populations of the developed world. The increased incidence of obesity is due in part to the ready availability of food in numerous retail outlets and westernised diets that have high saturated fat and lower fibre contents such that the food is energy dense. The lifestyle of the populations of the developed world has also become more sedentary with the increased mechanisation of society and the steady reduction of manual labour intensive industries. There now exists an energy imbalance between the energy intake from calorie dense foods and the reduced energy expenditure required for a sedentary lifestyle. Some of the excess energy intake is stored as fat in the adipose tissue, the accumulation of which over a period of time results in obesity and can be a significant contributory factor to other diseases and disorders.
Obesity is now recognised by the medical profession as a metabolic disease. In the USA, it is estimated that 25% of the adult population is considered clinically obese (Body Mass Index greater than 30). Obesity can be a debilitating condition which reduces the quality of life and increases the risk of related disorders such as diabetes, cardiovascular disease and hypertension. It has been estimated that $45 billion of US healthcare costs, or 8% per annum of total healthcare spend, is as a direct result of obesity. The traditional approaches to long term weight management such as diet and exercise have proved ineffective alone to control the spread of obesity. Today, more than ever, there is considerable interest in developing safe, effective drugs for the treatment of obesity.
Pharmacological approaches to the treatment of obesity have focused on either developing drugs that increase energy expenditure or drugs that reduce energy intake. One approach to the reduction of energy intake is to reduce the body""s ability to digest and absorb food, in particular fat. The key enzymes involved in the digestion of fat are hydrolytic enzymes. The most significant of the fat degrading enzymes are lipases, primarily, but not exclusively pancreatic lipase that is secreted by the pancreas into the gut lumen. The lipase inhibitor lipstatin has formed the basis of the anti-obesity drug, orlistat. Orlistat is the subject of published European Patent Application No. EP129748, which relates to compounds of formula: 
where A is xe2x80x94(CH2)5xe2x80x94 or: 
and their use in inhibiting pancreatic lipase and treating hyperlipaemia and obesity. Orlistat has as its major active moiety a beta-lactone group that reacts to form an ester with the side chain hydroxyl group of serine 152 within the active site of pancreatic lipase. Even if orlistat provides an effective method for treating obesity, there remains a need to provide alternative drugs and methods for use in the control and treatment of obesity, obesity-related disorders and non-medical weight loss. Inhibitors of enzymes involved in the degradation of fat are provided here and shown to be effective in the prevention and/or treatment of obesity, obesity-related disease and/or cosmetic weight loss.
U.S. Pat. No. 4,657,893 (Syntex) describes a broad class of 2-amino-4H-3,1-benzoxazin-4-ones of the formula: 
wherein R1 is hydrogen or lower alkyl, R2 and R3 are each independently hydrogen, halo, lower alkyl, hydroxy, lower alkoxy, lower thioalkyl, xe2x80x94NO2, xe2x80x94N(R1)2, xe2x80x94NR1COR1, xe2x80x94NHCON(R1)2 or NHCOOR1; and X is inter aliaxe2x80x94NHR where R is lower alkyl, lower alkenyl, lower alkynyl, optionally substituted lower cycloalkyl or optionally substituted phenyl lower alkyl. The compounds are said to be useful as serine protease inhibitors and to treat physiologic conditions and disease states known to involve serine proteases, or as contraceptives. The specification describes various conditions and diseases involving enzymatic pathways, including inflammation, arthritis, tumor cell metastasis, pulmonary emphysema, mucocutaneous lymph node syndrome, adult respiratory distress syndrome and pancreatitis. It is also suggested that the compounds may have antiparasitic, anticoagulant and/or antiviral activity. Similar compounds are also described by Krantz et al in J. Med. Chem. 1990 33:464-479.
2-Amino-4H-3,1-benzoxazin-4-ones as inhibitors of serine protease are also described by Hays et al in J. Med. Chem. 1998 41:1060-1067. This paper describes inter alia 2-(substituted phenyl)amino benzoxazinones, where the phenyl substituents include halogen, methyl, SMe, and OCF3, as well as certain 2-(heterocyclic)amino benzoxazinones. Some of these compounds are also described in U.S. Pat. No. 5,652,237 (Warner Lambert).
German OLS 2315303 (Bayer AG) describes the preparation of compounds of the formula 
where R is an alkyl or aryl residue which may be substituted by nitro, halogen, alkyl, alkoxy or an aryl group, and Rxe2x80x2 and Rxe2x80x3 are each independently hydrogen, halogen, nitro, optionally substituted alkyl, cycloalkyl, aralkyl, aryl, alkoxy or aryloxy groups. The only values of R exemplified are nitrophenyl and mono- and di-chlorophenyl. The compounds are said to be useful as intermediates for pharmaceuticals and plant protection agents.
We have now found that a particular class of benzoxazinone compounds has activity as lipase inhibitors
Accordingly, a first aspect of the invention provides a compound comprising formula (I) 
or a pharmaceutically acceptable salt, ester, amide or prodrug therof; in the manufacture of a medicament for the treatment of conditions which require the inhibition of an enzyme whose preferred mode of action is to catalyse the hydrolysis of an ester functionality; wherein in formula (I):
A is a 6 membered aromatic or hetero-aromatic ring;
R1 is a branched or unbranched alkyl (optionally interrupted by one or more oxygen atoms), alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, reduced arylalkyl, arylalkenyl, heteroaryl, heteroarylalkyl, heteroarylalkenyl, reduced aryl, reduced heteroaryl, reduced heteroarylalkyl or a substituted derivative therof wherein the substituents are one or more independently chosen from the group consisting of halogen, alkyl, halosubstituted alkyl, aryl, arylalkyl, heteroaryl, reduced heteroaryl, reduced heteroarylalkyl, arylalkoxy, cyano, nitro, xe2x80x94C(O)R4, xe2x80x94CO2R4, xe2x80x94SOR4, xe2x80x94SO2R4, xe2x80x94NR6R7, xe2x80x94OR6, xe2x80x94SR6, xe2x80x94C(O)CX1X2NR6R7, xe2x80x94C(O)NR4R5, xe2x80x94C(O)N(OR5)R6, xe2x80x94NR6C(O)R4, xe2x80x94CR6(NH2)CO2R6, xe2x80x94NHCX1X2CO2R6, xe2x80x94N(OH)C(O)NR6R7, xe2x80x94N(OH)C(O)R4, xe2x80x94NHC(O)NR6R7, xe2x80x94C(O)NHNR6R7, xe2x80x94C(O)N(OR5)R6, or a lipid or steroid (natural or synthetic), with the proviso that any hetero atom substituent in R1 and/or R2 must be separated from the exocyclic nitrogen atom by at least two carbon atoms (preferably saturated); and
R2 is hydrogen or is a group as defined above for R1;
and where:
R4 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, reduced heteroaryl, reduced heteroarylalkyl, xe2x80x94OR6, xe2x80x94NHCX1X2CO2R6 or xe2x80x94NR6R7;
R5 is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, reduced heteroaryl or reduced heteroarylalkyl;
R6 and R7 are independently selected from hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, heteroaryl, reduced heteroaryl, heteroarylalkyl, reduced heteroarylalkyl or xe2x80x94(CH2)n(OR5)m wherein n is 1 to 12, preferably 2 to 10, wherein m is 1-3 and R5 is most preferably C2-10 alkyl; and
X1 and X2 are independently hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, arylalkyl, heteroarylalkyl, reduced heteroaryl or reduced heteroarylalkyl.
In compounds of formula (I) any alkyl, alkenyl and alkynyl groups and moieties may be straight chain (unbranched) or branched chain. Straight chain alkyl, alkenyl and alkynyl groups or moieties may contain from 1 to 30 carbon atoms, eg. 1 to 25 carbon atoms, preferably 1 to 20 carbon atoms. Branched chain alkyl, alkenyl and alkynyl groups or moieties may contain from 1 to 50 carbon atoms, preferably 1 to 30 carbon atoms.
Preferred values for R1, R4, R5, R6, R7, X1 and X2 are as defined below for formulae (II) and (IIa). In particular, preferred values for R4, R5 and R6 are as defined for R13 and preferred values of R7 are as defined for R14 hereinbelow.
In this text, xe2x80x98reducedxe2x80x99, in the context of xe2x80x98reduced heteroarylxe2x80x99 and the like means fully or partially saturated.
Aryl groups include for example optionally substituted unsaturated monocyclic or bicyclic rings of up to 12 carbon atoms, such as phenyl and naphthyl, and partially saturated bicyclic rings such as tetrahydro-naphthyl. Examples of substituents which may be present on an aryl group include one or more of halogen, amino, nitro, alkyl, haloalkyl, alkoxy, phenoxy and phenoxy substituted by one or more of halo, alkyl or alkoxy.
A heteroaryl group or moiety may be for example an optionally substituted 5- or 6-membered heterocyclic aromatic ring which may contain from 1 to 4 heteroatoms selected from O, N and S. The heterocyclic ring may optionally be fused to a phenyl ring. Examples of heteroaryl groups thus include furyl, thienyl, pyrrolyl, oxazolyl, oxazinyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, pyridyl, triazolyl, triazinyl, pyridazyl, pyrimidinyl, pyrazolyl, indolyl, indazolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzoxazolyl, benzoxazinyl, quinoxalinyl, quinolinyl, quinazolinyl, cinnolinyl, benzothiazolyl, pyridopyrrolyl. Suitable substituents include one or more of halogen, oxo, amino, nitro, alkyl, haloalkyl, alkoxy, phenoxy and phenoxy substituted by one or more of halo, haloalkyl, alkyl or alkoxy.
A reduced heteroaryl group or moiety may be for example a fully or partially saturated derivative of the aforementioned heteroaryl groups. Examples of reduced heteroaryl groups thus include pyrrolidinyl, tetrahydrofuryl, tetrahydrothienyl and piperidinyl.
The compounds of the first aspect of the invention are useful inhibitors of enzymes involved in the degradation of fats. Preferably therefore the first aspect of the invention provides the use of a compound of formula (I) as defined hereinabove, or a pharmaceutically acceptable salt, ester, amide or prodrug thereof, in the manufacture of a medicament for the control or treatment of obesity, or obesity-related disorders or for promoting non-medical weight loss.
Preferably, a compound for use according to the first aspect of the invention is a compound of formula (II) 
or a pharmaceutically acceptable salt, ester, amide or prodrug therof; wherein:
R1, R4, R5, R6, R7, X1 and X2 are as defined above for formula I;
R2 is hydrogen or is a group as defined above for R1; and
R8, R9, R10, R11 are each independently hydrogen, halo, hydroxy, amino, nitro, cyano, or a group R1, as defined above;
or a group R12Q where Q is O, CO, CONH, NHCO, S, SO, SO2, or SO2NH2 and R12 is hydrogen or a group R1 as defined above;
or a group R1R2N where R1 and R2 are as defined above, with the proviso that any hetero atom substituent in R1 and/or R2 must be separated from the aromatic hetero atom substituent by at least two carbon atoms (preferably saturated).
In the compounds of formula (II):
R1 preferably represents phenyl substituted by a group selected from OR13, xe2x80x94COR13, CO2R13, SOR13, SO2R13, CONR13R14, NR14C(O)NR13, C1-10alkyl, C1-10alkoxy, haloC1-10alkyl, aryl, aryl C1-10alkyl, heteroaryl or heteroaryl C1-10alkyl; wherein R13 and R14 each independently represents hydrogen, C1-10alkyl, C2-10alkenyl, C2-10alkynyl, C3-6cycloalkyl,
C3-6cycloalkenyl, aryl, arylC1-10alkyl, heteroaryl, heteroarylC1-10alkyl, reduced heteroaryl or reduced heteroarylC1-10alkyl.
More preferably R1 represents phenyl substituted by OR13 or COR13 wherein R13 is preferably aryl, most preferably phenyl; phenyl substituted by xe2x80x94CO2R13 wherein R13 represents C1-10alkyl, preferably C1-6alkyl; or phenyl substituted by C6-10alkyl.
R2 preferably represents hydrogen or C1-10alkyl;
R8, R9, R10 and R11 preferably each independently represents hydrogen, halo, hydroxy, amino, nitro, cyano, thiol, C1-10alkyl, C1-10alkoxy, C1-10cycloalkyl, C1-10cycloalkoxy, C(O)R15, C(O)NR15R16, S(O)R15 or haloC1-10alkyl;
where R15 and R16 each independently represent hydrogen or C1-10alkyl.
R8 is hydrogen or halogen e.g. fluorine; most preferably hydrogen;
R9 is preferably hydrogen or lower branched or unbranched alkyl having 1 to 10 carbon atoms: cyclic alkyl having 3 to 6 carbon atoms, e.g. cyclopropyl; haloC1-6alkyl, e.g. trifluoromethyl; or a halogen, e.g. chlorine or fluorine;
R10 is preferably hydrogen, lower branched or unbranched alkyl having 1 to 10 carbon atoms e.g. ethyl, butyl or octyl: cyclic alkyl having 3 to 6 carbon atoms, e.g. cyclopropyl; haloC1-6alkyl, e.g. trifluoromethyl or a halogen, e.g. chlorine or fluorine;
R11 is preferably hydrogen, halogen, eg. fluorine; or branched or unbranched alkyl having 1 to 10 carbon atoms.
Preferably, in compounds of formula (II) at least one of R8, R9, R10 and R11 represents a substituent other than hydrogen. Thus, for example, R8 may represent a hydrogen atom and R9, R10 and R11 are as defined above. In a preferred embodiment each of R8 and R11 represents a hydrogen atom, and one or both of R9 and R10 represents a substituent as defined above.
Preferably, a compound for use according to the first aspect of the invention comprises a compound of formula (II) or a pharmaceutically acceptable salt, ester, amide or prodrug therof; wherein:
R1 is aryl e.g. optionally substituted phenyl or 2-naphthyl, or an aryl alkyl group wherein the alkyl moiety has up to 25 e.g. up to 20 carbon atoms, or an aryl aryl group; wherein the aryl alkyl group or the aryl aryl group may be separated by a spacer where the spacer can be an ester, amide, O, CH2, or a ketone and wherein any aryl group is preferably a phenyl, optionally substituted with alkyl, haloalkyl or halogen;
R2 is hydrogen or is a group as defined above for R1;
R8 is hydrogen or fluorine;
R9 is lower branched or unbranched alkyl having 1 to 10 carbon atoms; cyclic alkyl having 3 to 10 carbon atoms, e.g. cyclopropyl; haloalkyl, e.g. trifluoromethyl; or a halogen, e.g. chlorine or fluorine;
R10 is lower branched or unbranched alkyl having 1 to 10 carbon atoms; e.g. ethyl, butyl or octyl, cyclic alkyl having 3 to 10 carbon atoms, e.g. cyclopropyl; haloalkyl, e.g. trifluoromethyl; or a halogen, e.g. chlorine or fluorine;
R11 is hydrogen, lower branched or unbranched alkyl having 1 to 10 carbon atoms, or halogen, e.g. fluorine.
Most preferably, R1 is unsubstituted phenyl or phenyl substituted by a group selected from C1-8 alkyl, eg butyl, pentyl, hexyl or heptyl; halo-C1-8 alkyl, eg CF3; OR6 where R6 is phenyl or COR4 where R4 is phenyl or C1-8 alkyl.
In a second aspect the present invention provides novel compounds of formula (IIa): 
or a pharmaceutically acceptable salt, ester, amide or prodrug therof;
wherein:
R1a represents
(i) a C10-30 branched or unbranched alkyl, C2-30 alkenyl, C2-30 alkynyl, cycloalkenyl, aryl-C10-30 alkyl, aryl-C10-30 alkenyl, heteroaryl, heteroaryl-C1-30 alkyl, heteroaryl-C2-30 alkenyl, reduced aryl, reduced heteroaryl, reduced heteroaryl-C1-30 alkyl or a substituted derivative therof wherein the substituents are one or more independently chosen from the group consisting of halogen, C1-10 alkyl, halosubstituted C1-10 alkyl, aryl, aryl-C1-10 alkyl, heteroaryl, reduced heteroaryl, reduced heteroaryl-C1-10 alkyl, aryl-C1-10 alkoxy, cyano, nitro, xe2x80x94C(O)R13, xe2x80x94CO2R13, xe2x80x94SOR13, xe2x80x94SO2R13, xe2x80x94NR13R13, xe2x80x94OR13, xe2x80x94SR13, xe2x80x94C(O)NR13R14, and xe2x80x94NR14C(O)R13, with the proviso that any hetero atom substituent in R1 must be separated from the exocyclic nitrogen atom by at least two carbon atoms (preferably saturated); or
(ii) aryl substituted by one or more independently chosen from the group consisting of halosubstituted C1-10 alkyl, aryl, aryl-C1-10 alkyl, heteroaryl, reduced heteroaryl, reduced heteroaryl-C1-10 alkyl, aryl-C1-10 alkoxy, cyano, xe2x80x94C(O)R13, xe2x80x94CO2R13, xe2x80x94SOR13, xe2x80x94SO2R13, xe2x80x94NR13R14, xe2x80x94OR13 (providing that in this instance R13 does not represent aryl or alkyl), xe2x80x94SR13, xe2x80x94C(O)NR13R14, and xe2x80x94NR14C(O)R13 
wherein:
R13 and R14 each independently represents hydrogen, C1-10alkyl, C2-10alkenyl, C2-10alkynyl, C3-6cycloalkyl, C3-6cycloalkenyl, aryl, arylC1-10alkyl, heteroaryl, heteroarylC1-10alkyl, reduced heteroaryl or reduced heteroarylC1-10alkyl;
R2a is hydrogen or is a group as defined above for R1; and
R8a, R9a, R10a, R11a are as defined above for formula (II).
provided that:
when R1 represents a heteroaryl group it is not thiadiazolyl, triazolyl or thiazolyl and when R1 represents a reduced heteroaryl group it is not thiazolidinyl.
In the compounds of formula (IIa):
R1a preferably represents phenyl substituted by a group selected from OR13 (providing in this instance R13 does not represent alkyl or aryl), xe2x80x94COR13, CO2R13, SOR13, SO2R13, CONR13R14, NR14C(O)NR13, haloC1-10alkyl, aryl, aryl C1-10alkyl, heteroaryl or heteroaryl C1-10alkyl.
More preferably R1a represents phenyl substitued by COR13 wherein R13 is preferably aryl, most preferably phenyl; or phenyl substituted by xe2x80x94CO2R13 wherein R13 represents C1-10alkyl, preferably C1-6alkyl.
R2a preferably represents hydrogen or C1-10alkyl;
R8a, R9a, R10a and R11a preferably each independently represents hydrogen, halo, hydroxy, amino, nitro, cyano, thiol, C1-10alkyl, C1-10alkoxy, C1-10cycloalkyl, C1-10cycloalkoxy, C(O)R15, C(O)NR15R16, S(O)R4a or haloC1-10alkyl;
where R15 and R16 each independently represent hydrogen or C1-10alkyl.
R8a is hydrogen or halogen e.g. fluorine; most preferably hydrogen;
R9a is preferably hydrogen or lower branched or unbranched alkyl having 1 to 10 carbon atoms; cyclic alkyl having 3 to 6 carbon atoms; e.g. cyclopropyl, haloC1-6alkyl, e.g. trifluoromethyl or a halogen, e.g. chlorine or fluorine;
R10a is more preferably hydrogen, lower branched or unbranched alkyl having 1 to 10 carbon atoms e.g. ethyl, butyl or octyl; cyclic alkyl having 3 to 6 carbon atoms e.g. cyclopropyl, haloC1-6alkyl e.g. trifluoromethyl or a halogen e.g. chlorine or fluorine;
R11a is preferably hydrogen, halogen, eg. fluorine; or branched or unbranched alkyl having 1 to 10 carbon atoms.
Preferably, in compounds of formula (IIa) at least one of R8a, R9a, R10a and R11a represents a substituent other than hydrogen. Thus, for example, R8a may represent a hydrogen atom and R9a, R10a and R11a are as defined above. In a preferred embodiment each of R8a and R11a represents a hydrogen atom, and one or both of R9a and R10a represents a substituent as defined above. In a yet further embodiment the present invention provides compounds of formula (IIb) 
wherein
R8-R11 are as defined hereinbefore and
R20 represents C1-20alkyl, C1-20alkoxy, or optionally substituted phenoxy.
Preferred substituents for phenoxy include one or more of halo, CF3, lower alkyl and lower alkoxy groups.
When R20 represents an alkyl or alkoxy group this preferably contains from 6-12 carbon atoms.
In this embodiment R20 is most preferably phenoxy.
Preferred values of R8-R11 are as defined above.
Compounds of formula (IIb) represent a novel selection on the basis of their advantageous activity as lipase inhibitors.
Examples of pharmaceutically acceptable salts of the formula include those derived from organic acids such as methanesulphonic acid, benzenesulphonic acid and p-toluenesulphonic acid, mineral acids such as hydrochloric and sulphuric acid and the like, giving methanesulphonate, benzenesulphonate, p-toluenesulphonate, hydrochloride and sulphate, and the like, respectively or those derived from bases such as organic and inorganic bases. Examples of suitable inorganic bases for the formation of salts of compounds for this invention include the hydroxides, carbonates, and bicarbonates of ammonia, lithium, sodium, calcium, potassium, aluminium, magnesium, zinc and the like. Salts can also be formed with suitable organic bases. Such bases suitable for the formation of pharmaceutically acceptable base addition salts with compounds of the present invention include organic bases which are nontoxic and strong enough to form salts. Such organic bases are already well known in the art and may include amino acids such as arginine and lysine, mono-, di-, or trihydroxyalkylamines such as mono-, di-, and triethanolamine, choline, mono-, di-, and trialkylamines, such as methylamine, dimethylamine, and trimethylamine, guanidine; N-methylglucosamine; N-methylpiperazine; morpholine; ethylenediamine; N-benzylphenethylamine; tris(hydroxymethyl) aminomethane; and the like.
Salts may be prepared in a conventional manner using methods well known in the art. Acid addition salts of said basic compounds may be prepared by dissolving the free base compounds according to the first or second aspects of the invention in aqueous or aqueous alcohol solution or other suitable solvents containing the required acid. Where a compound of formula (I) contains an acidic function a base salt of said compound may be prepared by reacting said compound with a suitable base. The acid or base salt may separate directly or can be obtained by concentrating the solution eg. by evaporation. The compounds of this invention may also exist in solvated or hydrated forms.
The invention also extends to prodrugs of the aforementioned compounds. A prodrug is commonly described as an inactive or protected derivative of an active ingredient or a drug which is converted to the active ingredient or drug in the body.
Representative compounds according to the first and/or second aspects of the invention are those which include;
Compounds 2, 3, 5, 6, 8, 11-15 and 17-70 in Table 1 above are believed to be novel and as such represent preferred embodiments of the present invention.
Preferred compounds of formula (II) listed in Table 1 include compounds 1, 3, 5, 9, 17, 19, 20, 23 and 26.
Preferred compounds of formula (IIa) listed in Table 1 include compounds 11, 12, 14, 25, 29 and 30.
Preferred compounds of formula (IIb) listed in Table 1 include compounds 2, 6, 7, 8, 10, 15, 21, 24.
Particularly preferred compounds of formula (IIa) and (IIb) are:
2-(4-Phenoxyphenylamino)-4H-3,1-benzoxazin-4-one
2-(4-Butoxycarbonylphenylamino)-6-methyl-4H-3,1-benzoxazin-4-one
6-Methyl-2-(4-phenoxyphenylamino)-4H-3,1-benzoxazin-4-one
2-(4-Hexylphenylamino)-6-methyl-4H-3,1-benzoxazin-4-one
7-Methyl-2-(4-phenoxyphenylamino)-4H-3,1-benzoxazin-4-one
2-(4-Benzoylphenylamino)-7-methyl-4H-3,1-benzoxazin-4-one
2-(4-Phenoxyphenylamino)-7-trifluoromethyl-4H-3,1-benzoxazin-4-one
Preferred compounds of the invention listed above extend to the tautomers thereof, as well as (but not limited to) pharmaceutically acceptable salts, esters, amides or prodrugs thereof or a derivative with one or more lipid groups (natural or synthetic) attached.
A third aspect of the invention provides a process for the manufacture of any one or more of the novel compounds or derivatives according to the first and/or second aspects of the invention. Thus, the present invention provides a process for the preparation of a novel compound of formula (II) in particular a compound of formula (IIa) which process comprises:
Process (A) cyclising a compound of formula (III) 
wherein R1 and R8-R11 are as hereinbefore defined and R18 is hydrogen or C1-6alkyl.
or:
Process (B) reacting a compound of formula (IV) 
with an amine of formula (V)
R1R2NHxe2x80x83xe2x80x83(V) 
or:
Process (C) converting a compound of formula (I), (II), (IIa) or (IIb) into a different compound of formula (IIa) or (IIb), by, for example,
(i) reduction of a compound of formula (I), (II), (IIa) or (IIb) wherein any of R1, R8, R9, R10 and R11 contains an alkenyl or alkynyl group or moiety, to the corresponding alkyl or alkenyl group or moiety; or
(ii) alkylation of a compound of formula (I), (II), (IIa) or (IIb) where one or more of R8, R9, R10 and R11 represents a halogen atom.
Process (A) may be effected by reacting a compound (III) with a dehydrating agent in an organic solvent. Suitable dehydrating agents include sulphuric acid, and when R18 is hydrogen, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) or polymer supported EDC. The reaction may be effected at a temperature in the range 10 to 50xc2x0 C., preferably ambient temperature e.g. 20-30xc2x0 C. When polymer supported EDC is employed it may be removed by filtration at the end of the reaction, and the product isolated from solution by standard procedures, such as removal of the solvent and purification by flash column chromatography. Alternatively the cyclisation may be effected using concentrated sulphuric acid.
Alternatively, cyclisation according to process (A) may be effected by reaction with excess chloroformate or by addition of another cyclisation reagent, which promotes ring closure. Suitable cyclisation reagents include for example, methyl chloroformate, carbonyl diimidazole, acetic anhydride, phosgene, oxalyl chloride, thionyl chloride or a peptide coupling agent such as dicyclohexyl carbodiimide (DCC). The cyclisation reagent is preferably phosgene, triphosgene or thionyl chloride. When a chloroformate is employed this is preferably a low molecular weight chloroformate, on grounds of cost and ease of removing the resulting alcohol.
Compounds of the formula (III) may themselves be prepared according to a variety of methods. Thus for example a compound of formula: 
can be reacted with an isocyanate of formula (VII):
Oxe2x95x90Cxe2x95x90Nxe2x80x94R1xe2x80x83xe2x80x83(VII) 
The reaction is preferably carried out in an inert organic solvent, such as an ether e.g. tetrahydrofuran, an aliphatic hydrocarbon such as pentane or hexane; a halogenated hydrocarbon such as dichloromethane; or an aromatic hydrocarbon such as benzene or toluene, and usually at ambient temperature. The intermediate urea may cyclise directly in a xe2x80x98one potxe2x80x99 reaction, without isolation. Alternatively, if desired the urea may be isolated prior to cyclisation. Similarly any unreacted urea intermediate may be cyclised in a subsequent reaction step. It will be appreciated that the above reaction results in a compound (III) where R2 is hydrogen.
Alternatively a compound of formula (III) may be prepared by reacting an isocyanate of formula (VIII): 
(wherein R8, R9, R10, R11 and R18 are as hereinbefore defined) with an amine of formula (V) R1R2NH.
Compounds of formula (III) may also be prepared from compounds of formula (IX) 
by reaction with an amine R1R2NH.
Compounds (IX) may themselves be prepared by reacting a compound (VI) with an amine (V) in the presence of trichloromethyl chloroformate and in a solvent such as tetrahydrofuran or dimethyl formamide.
Process (B) may be effected by reacting a compound of formula (IV) with an amine R1R2NH in the presence of a base e.g. sodium hydroxide, followed by cyclisation, for example as described for process (A).
Compounds of formula (IV) may be obtained by cyclisation of a compound of formula (VI) wherein R18 is hydrogen using for example phosgene or a synthetic equivalent.
In process (C), reduction of an alkenyl or alkynyl group may be effected for example by catalytic hydrogenation using e.g. 10% palladium on charcoal in an alcoholic solvent, such as ethanol, under 1 atmosphere of hydrogen gas.
Alkylation according to process (C)(ii) may be effected using a Stille or other palladium catalysed cross-coupling process, using e.g. tetra-alkyl tin such as tetramethyl tin and PhCH2Pd(PPh3)2Cl in HMPA at elevated temperature e.g. 50-100xc2x0 C. Other halides or pseudohalides e.g. triflates may be employed as starting materials.
Further methodology for preparing 2-amino-1,3-benzoxazin-4-one derivatives is described in J. Med. Chem. 1990, 33(2):464-479 and J. Med. Chem. 1998 41:1060-1067, as well as U.S. Pat. No. 4,657,893.
A fourth aspect of the invention is a compound according to the first and/or second aspects of the invention (i.e. compounds of formulae (I), (II) and (IIa)), for use in medicine. Preferred features of the first and second aspects of the invention also apply to the fourth aspect. Further details of the fourth aspect of the invention are set out in the text which follows.
A fifth aspect of the invention relates to a compound according to the first and/or second aspects of the invention for use in the inhibition of an enzyme whose preferred mode of action is to catalyse the hydrolysis of an ester functionality. This includes both in vivo and in vitro uses and other uses such as industrial uses. Such an enzyme is one which catalyses the breakdown of a substrate containing an ester functionality by the addition of water, resulting in the cleavage of a chemical bond. Such enzymes are involved in key processes in the body. Enzymes according to this invention include lipases (hydrolyse fatty acid esters), esterases (hydrolyse esters) and phosphatases (hydrolyse phosphate esters).
The enzyme is preferably a lipase. Lipases include pancreatic lipase, gastric lipase, lipoprotein lipase, lingual lipase, adipose tissue lipase, hormone sensitive lipase, phospholipase A1, A2, B, C, D etc., hepatic lipase, and other triacyl, diacyl and monoacylglycerol lipases in the mammalian body. Many similar such lipases are also known in plants, fungi and microorganisms.
Also covered are esterase enzymes and phosphatase enzymes. Esterase enzymes include pig liver esterase, cholesteryl esterase, retinyl esterase, 1-alkyl-2-glycerophosphocholine esterase, carboxylic ester hydrolases and cholesterol esterase. Phosphatase enzymes include serine/threonine phosphatases PP1, PP2 and PP3, phosphoprotein phosphatase, myosin-light-chain phosphatase, protein phosphatase 2C and protein tyrosine phosphatase.
Compounds according to the invention, for use in medicine, are primarily for use in relation to the prevention and/or treatment of a medical condition such as obesity, hyperlipaemia, hyperlipidaemia and related diseases such as hyperglycaemia (type II diabetes), hypertension, cardiovascular disease, stroke, gastrointestinal disease and gastrointestinal conditions. Compounds according to the first and/or second aspects of the invention are useful in these and other conditions due to their ability to inhibit an enzyme whose preferred mode of action is to catalyse the hydrolysis of an ester functionality. The invention also relates to non-medical weight loss, such as cosmetic weight loss and includes improving bodily appearance in general. Throughout this text, the prevention and/or treatment of any disorder means any effect which mitigates any damage or any medical disorder, to any extent, and includes prevention and treatment themselves. The term xe2x80x9ctreatmentxe2x80x9d means any amelioration of disorder, disease, syndrome, condition, pain or a combination of two or more thereof.
Clearly, an important application of the invention is in relation to weight loss (of all kinds as described above) in humans. However, the invention applies to medical and non-medical weight loss in any animal whose metabolism of fat and fat derivatives involves an enzyme whose preferred mode of action is to catalyse the hydrolysis of an ester functionality. Thus, the invention has veterinary application and is particularly useful in relation to medical and non-medical weight loss in companion animals such as pet cats and dogs as well as in animals which provide meat for human consumption. In the case of the latter, the application of the present invention is to reduce fat content in order to provide a leaner meat product.
It is also believed that the compounds may be useful in reducing levels of toxins (e.g. dioxins and PCBs) stored in body fat. Without wishing to be bound by theory, it is believed that increasing the amount of undigested fat passing through the body enhances diffusion of toxins from fat stored in the body into fats in the blood, and thence into the intestine.
The fifth aspect of the invention has important applications. It includes test and diagnostic methods and the control and inhibition of unwanted enzymes, preferably lipases, in any process or in any product. The processes or products which preferably involve a lipase include processing of agricultural commodities (e.g. oilseeds), recovery and isolation of enzymes from biotechnological processes (e.g. involving lysis of microorganisms), the manufacture and extraction of crude oil (especially oil and plastics), the industrial manufacture of triglycerides or other fats, manufacture of healthcare goods which comprise surfactants, soap or detergent (e.g. bath oils, creams), the manufacturing and processing of liposomes (e.g. healthcare products, diagnostics, gene therapy), the treatment of industrial waste (e.g. paper effluent treatment) and preventing the degradation of foodstuff which comprises a fat (e.g. chocolate processing). Thus, the invention also relates to these products and processes, e.g. a foodstuff which comprises a compound according to the first aspect of the invention, in particular foodstuffs which have a high fat content such as cakes, biscuits, pastry-products and the like and chocolate products. The preferred features of the fifth aspect of the invention, including the preferred enzymes are as discussed for the previous aspects of the invention.
A sixth aspect of the invention provides a composition comprising a novel compound according to the first and second aspects of the invention, in combination with a pharmaceutically acceptable carrier or diluent. Suitable carriers and/or diluents are well known in the art and include pharmaceutical grade starch, mannitol, lactose, magnesium stearate, sodium saccharin, talcum, cellulose, glucose, sucrose (or other sugar), magnesium carbonate, gelatin, oil, alcohol, detergents, emulsifiers or water (preferably sterile). The composition may be a mixed preparation of a composition or may be a combined preparation for simultaneous, separate or sequential use (including administration).
The compounds according to the invention for use in the aforementioned indications may be administered by any convenient method, for example by oral (including by inhalation), parenteral, mucosal (e.g. buccal, sublingual, nasal), rectal or transdermal administration and the compositions adapted accordingly.
For oral administration, the compounds can be formulated as liquids or solids, for example solutions, syrups, suspensions or emulsions, tablets, capsules and lozenges.
A liquid formulation will generally consist of a suspension or solution of the compound or physiologically acceptable salt in a suitable aqueous or non-aqueous liquid carrier(s) for example water, ethanol, glycerine, polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring or colouring agent.
A composition in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations. Examples of such carriers include magnesium stearate, starch, lactose, sucrose and microcrystalline cellulose.
A composition in the form of a capsule can be prepared using routine encapsulation procedures. For example, powders, granules or pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively, a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), for example aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule.
Compositions for oral administration may be designed to protect the active ingredient against degradation as it passes through the alimentary tract, for example by an outer coating of the formulation on a tablet or capsule.
Typical parenteral compositions consist of a solution or suspension of the compound or physiologically acceptable salt in a sterile aqueous carrier or non-aqueous or parenterally acceptable oil, for example polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration.
Compositions for nasal or oral administration may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations typically comprise a solution or fine suspension of the active substance in a physiologically acceptable aqueous or non-aqueous solvent and are usually presented in single or multidose quantities in sterile form in a sealed container, which can take the form of a cartridge or refill for use with an atomising device. Alternatively the sealed container may be a unitary dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve which is intended for disposal once the contents of the container have been exhausted. Where the dosage form comprises an aerosol dispenser, it will contain a pharmaceutically acceptable propellant. The aerosol dosage forms can also take the form of a pump-atomiser.
Compositions suitable for buccal or sublingual administration include tablets, lozenges and pastilles, wherein the active ingredient is formulated with a carrier such as sugar and acacia, tragacanth, or gelatin and glycerin.
Compositions for rectal or vaginal administration are conveniently in the form of suppositories (containing a conventional suppository base such as cocoa butter), pessaries, vaginal tabs, foams or enemas.
Compositions suitable for transdermal administration include ointments, gels and patches, and injections, including powder injections.
Conveniently the composition is in unit dose form such as a tablet, capsule or ampoule.
The compositions of the sixth aspect of the invention are useful in the prevention and/or treatment of obesity, obesity-related disorder, other medical weight loss and non-medical related weight loss. Preferred features of this aspect of the invention are as described above for the first to fifth aspects of the invention.
A seventh aspect of the invention provides a process for the manufacture of a composition according to the sixth aspect of the invention. The manufacture can be carried out by standard techniques well known in the art and involves combining a compound according to the first or second aspect of the invention and the pharmaceutically acceptable carrier or diluent. The composition may be in any form including a tablet, a liquid, a capsule, and a powder or in the form of a food product, e.g. a functional food. In the latter case the food product itself may act as the pharmaceutically acceptable carrier.
An eighth aspect of the invention provides a method for the prevention and/or treatment of obesity or an obesity-related disorder, the method comprising the administration of a compound according to the first or second aspect of the invention, preferably in combination with a pharmaceutically acceptable carrier or diluent (as per the sixth aspect of the invention). Obesity-related disorders include hyperlipeamia, hyperlipideamia, hyperglycaemia, hypertension, cardiovascular disease, stroke, gastrointestinal disease and gastrointestinal conditions. The compound or composition is preferably administered to a patient in need thereof and in a quantity sufficient to prevent and/or treat the symptoms of the condition, disorder or disease. For all aspects of the invention, particularly medical ones, the administration of a compound or composition has a dosage regime which will ultimately be determined by the attending physician and will take into consideration such factors such as the compound being used, animal type, age, weight, severity of symptoms, method of administration, adverse reactions and/or other contraindications. Specific defined dosage ranges can be determined by standard design clinical trials with patient progress and recovery being fully monitored. Such trials may use an escalating dose design using a low percentage of the maximum tolerated dose in animals as the starting dose in man.
The physiologically acceptable compounds of the invention will normally be administered in a daily dosage regimen (for an adult patient) of, for example, an oral dose of between 1 mg and 2000 mg, preferably between 30 mg and 1000 mg, e.g. between 10 and 250 mg or an intravenous, subcutaneous, or intramuscular dose of between 0.1 mg and 100 mg, preferably between 0.1 mg and 50 mg, e.g. between 1 and 25 mg of the compound of the formula (I) or a physiologically acceptable salt thereof calculated as the free base, the compound being administered 1 to 4 times per day. Suitably the compounds will be administered for a period of continuous therapy, for example for a week or more.
A ninth aspect of the invention provides a cosmetic method for maintaining a given weight, or for cosmetic weight loss, the method comprising the administration of a compound according to the first aspect of the invention, preferably in combination with a pharmaceutically acceptable carrier or diluent (as per the fifth aspect of the invention). The xe2x80x9cmedicamentxe2x80x9d is preferably administered to a patient in need thereof and in a quantity sufficient to maintain a given weight or for cosmetic weight loss.
The eighth and ninth aspects of the invention relate to methods of treatment of humans and other animals, in particular companion animals and other animals which provide meat for human consumption, such as cattle, pigs and sheep (all of any age).
The invention will now be described with reference to the following non-limiting examples.
Biological Test Methods and Results
Test Compounds
The benzoxazinone compounds used in the following tests are identified by the reference number assigned in Table 1 hereinbefore.
Measurement of Lipase Activity using a Quinine Diimine Dye Colorimetric Assay
The inhibitory activity of the selected compounds to pancreatic lipase was measured in the following assay available from Sigma Ltd (Lipase PS(trademark), catalog number 805-A): 
The glycerol released from the action of pancreatic and monoglyceride lipase was oxidised to release H2O2. The peroxidase reaction step then produces a quinine dye which is pink in colour and absorbs light at a wavelength of 550 nm.
Inhibitor
Individual compounds were dissolved in DMSO (dimethyl sulphoxide) at 10 mM. DMSO was used to avoid any problems with compounds being water-insoluble.
For individual compounds, the IC50 (concentration at which lipase activity is inhibited to one half of the maximum) was calculated by measuring the inhibitory activity from log-dose response curves using a range of inhibitor concentrations.
Results
A range of compounds were assayed in the quinine diimine dye colorimetric assay which provides a rapid method to measure lipase inhibitory activity. None of the compounds tested interfered with the colorimetric reaction, i.e. they did not give false positive results.
A range of inhibitory activities for the tested benzoxazinone compounds were observed, indicating that these compounds are inhibitors of human pancreatic lipase. The following compounds had IC50""sxe2x89xa61 xcexcM: 1-3, 5-12, 14, 15, 17, 19-21, 23-26, 28-30.
Measurement of Lipase Enzyme Activity using a NaOH Titration Method
The inhibitory activity of the selected compounds to pancreatic lipase was measured in the assay described in Pasquier et al., 1986, Vol 7, Nutritional Biochemistry, 293-302.
Log dose/response curves were constructed using a range of inhibitor concentrations.
Results
Selected benzoxazinone compounds were tested in the NaOH titration assay. In this assay, the activity of porcine pancreatic lipase in a system containing lipid micelles is recorded. These conditions are therefore similar to those encountered in the gastrointestinal tract.
A range of inhibitory activities were observed for the tested benzoxazinone compounds in this assay indicating that these compounds are inhibitors of porcine pancreatic lipase. The following compounds had an IC50xe2x89xa62 xcexcM: 1-3, 5, 8, 11, 12, 14-20, 24, 26, 28, 29, 30.
Thus, the results demonstrate that the tested benzoxazinones are inhibitors of fat digestion and that these compounds may be particularly suitable for the treatment of obesity.
Mouse Model Assay
Compound 24 was assayed in a mouse model as described by Isler et al., British Journal of Nutrition, 1995, 73:851-862 and was found to be a potent lipase inhibitor.
Synthesis of Intermediates
Synthesis of 4-Substituted Anthranilic Acids
Example: 4-octyl anthranilic acid (4-octyl-2-aminobenzoic acid)
Method based on that of L. A. Paquette et al. J.Am.Chem.Soc. 99, 3734 (1981) 
A solution of 1-bromo-4-octylbenzene (9.9 g, 36 mmol) in sulfuric acid (20 ml) was cooled in an ice bath. To this was added nitric acid (1.44 ml, 36 mmol). The ice bath was removed and the mixture stirred at room temperature for 20 minutes. A further portion of nitric acid was added (0.07 ml, 1.75 mmol), stirring being continued for a further 20 min. The mixture was poured into aqueous potassium carbonate, which was extracted with ethyl acetate. The organic extract was washed with saturated aqueous potassium carbonate, water and brine then dried (MgSO4) and concentrated. Purification of the crude product by flash chromatography (1% EtOAc/hexane) removed the unwanted (major) regioisomer and afforded the desired material as a yellow oil (1.7 g, 5.4 mmol). 
The substrate (1.7 g, 5.4 mmol), copper (I) cyanide (0.533 g, 5.9 mmol) and pyridine (20 ml) were refluxed at 150xc2x0 C. for 2 days. Concentration in vacuo and purification by flash chromatography (10% to 20% EtOAc/hexane) gave the desired material as a brown oil (739 mg, 2.8 mmol) 
The substrate (694 mg, 2.7 mmol) was heated at 150xc2x0 C. in a mixture of water (2 ml), AcOH (1 ml) and sulfuric acid (1 ml) for 2 days. The mixture was extracted with ethyl acetate, the organic phase being washed with water (xc3x972), dried (Na2SO4) and concentrated to give the desired material (744 mg, 2.7 mmol). 
The starting material (744 mg, 2.7 mmol) was dissolved in ethanol (10 ml) and to this was added a slurry of 10% palladium on charcoal (40 mg) in ethanol (4 ml). The flask was flushed with nitrogen then hydrogen (1 atm) after which stirring was maintained overnight. Further portions of catalyst (5 mg and 25 mg) were added, the reaction being complete after a further 24 h. The reaction mixture was filtered through celite, thoroughly rinsing with methanol and ethyl acetate. Concentration gave the anthranilic acid (597 mg, 2.4 mmol) of sufficient purity for use without further purification; xcex4H (400 MHz, CDCl3) 0.79-0.81 (3H, m, Me), 1.12-1.36 (10H, m, 5xc3x97CH2), 1.52 (2H, br.s, ArCH2CH2), 2.45 (2H, br.s, ArCH2), 6.42 (2H, br.s, 2xc3x97ArH), 7.74 (1H, br.s, ArH); m/z (ES+) 250 (MH+).
Synthesis of Substituted Phenyl Isocyanates
Example: Preparation of 4-octylphenyl isocyanate 
A solution of 4-octylaniline (0.3 ml, 1.3 mmol) and diisopropylamine (0.205 ml, 5.2 mmol) in THF (5 ml) was cooled to xe2x88x9210xc2x0 C. A 20% solution of phosgene in toluene (1.3 ml, 2.6 mmol) was added, then the mixture was allowed to warm to r.t. and maintained at that temperature for 3 h. Excess phosgene was removed under a stream of nitrogen (scrubbed on exit with NaOH(aq)) to give a solution of the crude isocyanate, which was used directly in the next step.
4-Benzoylphenylisocyanate was prepared by an analogous procedure from the corresponding aniline.
Substituted 4-phenoxyphenyl isocyanates can be prepared from the corresponding amines by known procedures.
Synthesis of Compounds According to the Invention